the nmr spectra of azo dyes, 5-arylazobarbituric (5a-g), 5-arylazo-1,3-dimethylbarbituric(6a-g) and 5-arylazothiobarbituric acids (7a-g) were studied in dmso-d6 in differentconcentrations. an intramolecular hydrogen bond was observed and indicating that thehydrazone forms is mostly predominant. the peak of the hydrazone proton was severelybroadened and its chemical shift appeared at down field ...

The NMR spectra of azo dyes, 5-arylazobarbituric (5a-g), 5-arylazo-1,3-dimethylbarbituric(6a-g) and 5-arylazothiobarbituric acids (7a-g) were studied in DMSO-d6 in differentconcentrations. An intramolecular hydrogen bond was observed and indicating that thehydrazone forms is mostly predominant. The peak of the hydrazone proton was severelybroadened and its chemical shift appeared at down field ...

The title compound, C23H24N4OS, contains a highly asymmetric bifurcated intramolecular hydrogen bond between the hydroxy group and two pyrazole N atoms. The compound associates into centrosymmetric dimers in the crystal through two unique C-H...pi interactions, which are in turn linked into a (6,3)-network through an additional intermolecular C-H...N hydrogen bond.

Molecular structure, isomerism, conformational stability and intramolecular hydrogen bonding (IHB) of cis-enol forms of 1-(n-pyridyl)butane-1,3-diones (nPBD) (n = 2, 3, or 4) have been investigated by means of density functional theory (DFT) calculations. Energy differences for all possible nPBD cis-enol forms of isomers with respect to the most stable form of the correspondin...

In the mol-ecule of the title compound, C(11)H(14)N(2)O(4), a bifurcated intra/intermolecular N-H⋯(O,O) hydrogen bond occurs.The intramolecular component results in a non-planar six-membered ring with a flattened-boat conformation. In the crystal structure, the inter-molecular interaction links the mol-ecules into chains parallel to the b axis.

In the title compound, C(17)H(14)ClF(2)NO(2), the amino-acrylo-yloxy group makes dihedral angles of 47.55 (11)° with the 4-chloro-phenyl group and 8.74 (12)° with the difluoro-phenyl group; the dihedral angle between the rings is 52.32 (11)°. The structure of the title compound reveals a Z configuration with respect to the C=C double bond in the amino-acrylate fragment. A bifurcated intramolecu...

molecular structure, isomerism, conformational stability and intramolecular hydrogen bonding (ihb) of cis-enol forms of 1-(n-pyridyl)butane-1,3-diones (npbd) (n = 2, 3, or 4) have been investigated by means of density functional theory (dft) calculations. energy differences for all possible npbd cis-enol forms of isomers with respect to the most stable form of the corresponding isomer have been...

The mol-ecule of the title compound, C(21)H(16)N(2)O, exists in the keto form and the C=O and N-H bonds are mutually cis in the crystal structure, although an enol form would be possible through tautomerism. The dihedral angle between the quinoline and the naphthalene systems is 22.04 (2)°. A bifurcated intramolecular N-H⋯(O,N) hydrogen bond is present.

In the crystal structure of the title salt, C7H7Cl2N2O2+.Cl-, the chloride anions participate in extensive hydrogen bonding with the aminium cations and indirectly link the molecules through multiple N+-H...Cl- salt bridges. There are two independent molecules in the asymmetric unit, related by a pseudo-inversion center. The direct intermolecular coupling is established by C-H...O, C-H...Cl and...